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Abstract

The andosols of south-central Chile (36-42°S) are developed on yellow-brown loams that cover the
region with a thickness of several meters. In the literature, several hypotheses concerning the
nature, origin, mode of transport and deposition of the andosol parent material have been advanced
but no general agreement has been found. In this paper, we test these hypotheses by analyzing new
representative outcrops located around Icalma (38°50’S) and Puyehue (40°40’S) lakes by a plurimethodological
approach. Our data demonstrate that the andosol parent material has the typical
mineralogical and geochemical signature of the regional volcanism and that these deposits are postglacial
in age. The grain size of the deposits and the morphology of the coarse grains evidence that
most of these particles haven’t been re-transported by wind but are direct volcanic ash falls
deposited throughout the Late Glacial and Holocene. Because of the prevailing westerly winds,
most of them have been transported to the East. Following the deposition of the volcanic particles,
weathering and pedogenetic processes have transformed part of the volcanic glasses and
plagioclases into allophane and have wiped out the original layering. This work demonstrates that
most of the andosols that occur in the Andes and in the eastern part of the Intermediate Depression
of south-central Chile are developed on volcanic ashes directly deposited by successive volcanic
eruptions throughout the Late Glacial and Holocene.

We document the mineralogical and geochemical composition of tephra layers identified in
the late Quaternary sediments of Puyehue Lake (Southern Volcanic Zone of the Andes, Chile,
40°S) to identify the source volcanoes ...

After the 1960 M9.5 Valdivia, Chile earthquake, three types of geodetic observations were made during four time periods at nearby locations. These post-seismic observations were previously explained by post-seismic afterslip ...

The Ocean Reference Station at 20°S, 85°W under the stratus clouds west of northern Chile is
being maintained to provide ongoing climate-quality records of surface meteorology, air-sea
fluxes of heat, freshwater, and ...

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